Fingerprints are inborn and invariable characteristics of a human body, and are unique to everyone and can be used to distinguish from others. Each fingerprint comprises a series of ridges and valleys at skin surface of fingertip, and the ridges and the valleys generally include details of ridge bifurcation, ridge ending, arch (e.g. tented arch), left loop, right loop, whorl or twin loop, etc., these details determine uniqueness of fingerprint. Fingerprint identification technology is developed due to the uniqueness of fingerprint, and is an earlier technology that has been used for personal identity authentication. Optical imaging, thermal sensor, human body infrared sensor and so on are widely used for fingerprint acquisition and input.